Amazon expands one-hour delivery to Miami and Baltimore

Amazon has expanded its one-hour delivery service to Baltimore and Miami, after a four-month test run in parts of New York City.

Amazon(AMZN) said that its service, Prime Now, expanded to "select Baltimore and Miami zip codes" on Thursday and will soon expand to wider neighborhoods in those cities.

Amazon said the service is available to Prime members (costing $99 a year) and can be accessed through an app on iOS and Android devices. One-hour delivery costs $7.99 and two-hour delivery is free. The service is available from 8 a.m. to 10 p.m., seven days a week.

Prime Now was launched in December as a test in lower Manhattan, and it was later expanded to Brooklyn.